Mammalian fetal sensory development comes in an invariant series, with the tactile/kinesthetic and chemosensory systems the earliest functioning and responsive to stimulation, implicating the importance of these foundational sensory systems for later development. Olfaction is essential for neonatal behavioral adaptation in many mammals, including humans. Experiments show that newborns recognize, and are soothed by, the smell of amniotic fluid. Provision of the mother's smell with breast pads, handkerchiefs she has worn, breast milk on a cotton ball or cotton applicator, or other means of providing odor and taste input can facilitate recognition by the infant's mother at a later time and does not appear to be detrimental to the stability of the infant.